Polyimides have been widely used, for example, in the field of electronic communication and OA appliances as well as in the field of aerospace because they have more excellent heat resistance than other organic polymers. The polyimides have recently been desired to have not only excellent heat resistance but also a variety of performance for a wide range of uses.
Photosensitive polymers can be prepared by reacting existing polymers with photosensitive groups so that the photosensitive group can function as pendant groups. A representative example of the photosensitive polymers prepared by this reaction is polyvinyl cinnamate invented by Minsk et al. of Eastman Kodak Company, which is disclosed in J. Appl. Polymer Sci., 2, 302 (1959). Polyvinyl cinnamate is prepared by the esterification of polyvinyl alcohol using cinnamic acid chloride. When this polymer is irradiated with light, it is cross-linked and cured to form cyclobutane rings.
However, polyimides with a cinnamoyl derivative skeleton at a side chain thereof are reported only in Japanese Unexamined Patent Publication No. (Patent Kokai No.)55-45747 (1980).
Since a reactive group has a double bond or triple bond, it is conceivable to introduce it into polyimide so as to use the polyimide as thermosetting resin. However, there have been few cases where a reactive group is introduced into polyimide to use the polyimide as thermosetting resin.
If a photosensitive group is introduced into at least one of an acid dianhydride component and a diamine component, cross-linking density can be increased. However, there have been only a few cases where a photosensitive group is introduced into both of them.
Further, since polyimide has a relatively high water absorption, problems may arise when it is used in the aforementioned fields, and thus it has only limited uses. In order to solve such problem, Japanese Unexamined Patent Publication No. (Patent Kokai No.) H05-346585 (1993) discloses that a fluoroalkyl group is introduced into a diamine component, and Japanese Unexamined Patent Publication No. (Patent Kokai No.) H08-220541 (1996) discloses that an alkyl group is introduced into a diamine component. However, a diamine with two groups selected from alkyl groups and fluoroalkyl groups in a molecule thereof is not known. Further, a diamine with a reactive group bonded to an end of the alkyl group or fluoroalkyl group is not also known.
An object of the present invention is to provide a novel acid dianhydride and a novel diamine with a reactive group introduced thereinto and a novel reactive group containing polyimide having the acid dianhydride and the diamine as monomer components. Specifically, an object of the present invention is to provide an acid dianhydride with a reactive group bonded through a C2 to C30 alkylene group and a C4 to C30 fluoroalkylene group, a novel diamine having two groups selected from alkylene groups having a carbon number of 6 to 30 and fluoroalkylene groups having a carbon number of 4 to 30 in a molecule thereof, and a diamine with a reactive group at the end of a side chain thereof.
Further, another object of the present invention is to provide a novel polyimide composition containing at least one of the aforementioned acid dianhydride and the diamine components in a molecule thereof. A further object of the present invention is to provide a novel polyimide composition having both photoreactivity and thermoreactivity specific to a reactive group selected from a skeleton derived from cinnamic acid, chalcone, furylacryloyl, benzalacetophenone, stilbene, coumarin, or pyrone, an organic group such as allyl, propargyl, ethinyl, CH2═CH—, and CH2═C(CH3)—, or a skeleton derived therefrom, and a novel diamine and a novel acid dianhydride to be contained in the novel polyimide.
The inventors of the present invention have studied intensively, found that their intended objects can be achieved by preparing a diamine and an acid dianhydride of a special structure and a polyimide containing such diamine and acid dianhydride, and consequently they have accomplished the present invention.